I've just updated my wife's 3GS to iOS 5.1 from iOS 4. The restore seem to only restore the messages/photo roll and some other settings. I don't see most of the apps but the most important part is the contacts are missing. This is why I'm looking for the iPhone backup that iTunes creates before updating the software.

I currently have tried the following:

Turn off iCloud

Turn on then off iCloud

Adding a Contact

Restoring from the last backup file(without timestamp)

Reset to Factory defaults and restoring

Copying from Sim (Has some older contacts, not the recent ones)

Using iBackupBot to browse the backups (only iOS5 backups seem to be there)

Here are some other valid points:
1. The iPhone isn't regularly synced
2. I created a backup before updating the OS I can't find it anywhere now
3. There's no contacts on the Mac's Address Book.
4. There is only Sim contacts in the iCloud sync
5. iBackupBot shows me there are no other contacts other than the Sim ones that got synced to iCloud
6. There are existing SMS-es without Contact Names
7. I can try to correlate the SMSes with names but it will not give me the full contact list.

Since the Messages are restored, the contacts must be kept somewhere can anyone help me? I'm pretty sure I just need to find the backup that was created for the Update and somehow grab all the contacts maybe using ibackupbot.

Exactly because I have found myself in situations like this, I keep a backup of my iPhone contacts on my PC via Windows Contacts. In the future you can copy iPhone contacts to your PC with third party apps or via iTunes sync.

The location of your iPhone backup files made by iTunes is as follows:

If you are on WinXP - C:\Documents and Settings\user\Application Data\Apple Computer\MobileSync\Backup

If you are on WinVista/Win7 - C:\Users\user\AppData\Roaming\Apple Computer\MobileSync\Backup

If you are on MacOS - ~/Library/Application Support/MobileSync/Backup/

If you are trying to access your iPhone backup files with a third-party application, there are lots such of apps I believe one of them was called iPhone Browser.